HOCKENHEIM, Germany -- Lewis Hamilton has revealed that a Formula One team other than Mercedes approached him about a 2019 contract, but he insists he did not take the offer seriously.

Mercedes announced Hamilton's new two-year contract on Thursday that will see the four-time world champion stay at the team until the end of 2020. While the deal was never really in doubt, negotiations over details dragged over several months after the basic contract was finalised earlier this year.

Ferrari and Red Bull were the only other viable options for Hamilton given the gulf in performance between the top three and the midfield, and he revealed that one team attempted to open negotiations with him.

"In terms of the other guys approaching, one did but I didn't give it any time," Hamilton said.

Lewis Hamilton of Great Britain and the Mercedes AMG Petronas F1 Team in the paddock during previews ahead of the Monaco Formula One Grand Prix in May. Marco Canoniero/LightRocket/Getty Images

He went on to explain that the two-year duration of the deal was a "strategic decision," as Formula One has yet to finalise commercial contracts with teams beyond the end of 2020.

"Yeah, I personally wanted to do two [years]. We were talking about doing three, but in Formula One the shapes are shifting a little bit. Formula One is not committed to all the teams moving forwards beyond 2021 just yet, and I am interested to see how all of that plays out.

"It didn't make sense for me to commit into the unknown, even though it's easy for me to imagine me being at Mercedes, but commercially everything could shift or not. You don't want to put yourself in a corner where you can't move from, so it's a strategic decision for myself."

Unlike most drivers in F1, Hamilton negotiates his contracts himself and said it had helped build trust with Mercedes team boss Toto Wolff.

"The one thing that shows is the trust we have between each other. I said from day one, 'Look, I'm not talking to anyone else, I'm not investigating to see what other options there are, I'm not playing you against anyone else. While I know there are drivers calling you -- which I expect -- I also trust that you're not thinking to do anything else, so we can take our time.'

"It's been great and I'm really happy with the process. I enjoy that negotiation phase -- it's intense, it's a learning experience, you learn a lot about the person that you're speaking to. It's an interesting dynamic but one that I've enjoyed doing. This was my third contract with the team and I'm just really, really excited about the plan.

"My mental focus of what I want to do and achieve in this team with them, which I'm not going to elaborate on, but I'm excited about this journey over the next couple of years. I think we can do some great things."